Stud fastener assembly with integral lockring

ABSTRACT

A stud fastener assembly having both ends thereof threaded and a lockring in slidable but captive engagement between the said threaded ends so that said lockring is not disengageable therefrom and a method of making the same whereby the lockring is slipped onto the stud fastener subsequent to threading one end thereof and thereafter threading the opposite end of said fastener.

United States Patent [72] inventors Jose Rosan, Sr.

San Juan Capistrano; Jose Rosan, Jr., Newport Beach, both of Calif. [21]Appl. No. 32,081 [22] Filed Apr. 27, 1970 [45] Patented Dec. 28, 1971[73] Assignee Rosan Engineering Corp.

Newport, Calif. by said Jose Rosan, Jr.

[54] STUD FASTENER ASSEMBLY WITH INTEGRAL LOCKRING 6 Claims, 6 DrawingFigs.

[52] U.S.Cl Isl/41.73, 151/8,151/54,10/27 [51] Int. Cl Fl6b 39/02 [50]Field ofSearch 15l/41.73, 8, 54, 55; 285/92, 23

[56] References Cited UNITED STATES PATENTS 769,199 9/1904 Tower 151/682,400,348 5/1946 Greene... 151/41.73 2,788,830 4/1957 Rosan 151/41.733,215,183 11/1965 Diet1ein., 151/41.73 3,259,161 7/1966 Rosan..151/41.73 3,259,163 7/1966 Rosan 151/41.73

FOREIGN PATENTS 1,091,566 10/1954 France 151/4l.73 1,516,595 1/1968France 151/23 Primary ExaminerMarion Parsons, Jr. Attorney-Roman A. DiMeo ABSTRACT: A stud fastener assembly having both ends thereof threadedand a lockring in slidable but captive engagement between the saidthreaded ends so that said lockring is not disengageable therefrom and amethod of making the same whereby the lockring is slipped onto the studfastener subsequent to threading one end thereof and thereafterthreading the opposite end of said fastener.

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STUD FASTENER ASSEMBLY WITH INTEGRAL LOCKRING With the advent of moresophisticated motors, engines and the like having speeds of highrevolution and the attendant vibration problems resulting therefrom, ithas become increasingly necessary to obtain extraneously installed studscapable of being locked into place without the possibility of beingloosened due to the aforesaid high vibrational forces. This problem hasbeen solved by using a lockring in conjunction with the stud to form astud fastener assembly, said lockring being externally and internallyserrated whereby the internal serrations thereof engage cooperatingserrations on the stud body and the lockring. After the lockring isdisplaced into integral engagement with the workpiece, since itsexternal serrations engage the workpiece material, rotation of thelockring,

and a fortiori the stud, is prohibited, and concomitantly helicaldisplacement of the fastener is also prohibited.

However, an inventory and installation problem could conceivably occurby the use of separate nointegral lockring in conjunction with the studfastener. The instant invention anticipates and avoids this problem bymaintaining the lockring in permanent limited slidable engagement withthe threaded ends of the stud fastener. This is achieved as willhereinafter be more fully described by threading one end ofa stud blank,placing the lockring onto the stud blank over the nonthreaded oppositeend, and thereafter threading the nonthreaded end of the stud blank.

An additional important feature of this invention is that while thelockring is in slidable engagement with the stud body its longitudinalmovement is limited in either direction by the threads on the stud bodyformed on opposite sides of the lockring. Thus, when the stud isthreaded into a workpiece bore the depth of its installation will belimited by the slidable lockring contacting the bottom threadconvolution of the threads of the external portion of the stud, therebyproviding a positive means for installing the studs of the instantinvention to a uniform depth.

Accordingly, the principal object of this invention is to provide a studfastener assembly which can be permanently locked into a workpiece bymeans of a serrated lockring wherein the lockring is in captiverelationship with the stud body.

Another object is to provide a stud fastener assembly which can bepermanently locked into a workpiece by means of a serrated lockringwherein the lockring is captive, but in movable relationship with thestud fastener body.

Still another object is to provide a stud fastener assembly which can bepermanently locked in a workpiece by means of a serrated lockringwherein the stud fastener is further provided with means for positivelyinstalling the same at a uniform depth.

Other objects and advantages will be readily apparent from thedescription taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is an elevational, partly sectioned, view of the stud fastenerassembly of the instant invention threaded into a workpiece, but priorto displacing the serrated lockring into locking position into theworkpiece material;

FIG. 2 is an elevational, partly sectioned, view of the stud fastenerassembly shown in FIG. 1, illustrating the lockring displaced into theworkpiece material in locking position;

FIG. 3 is an elevational view of the stud body of the stud fastenerassembly of FIG. 1;

FIG. 4 is a cross-sectional view of the stud body shown in FIG. 3 takenon the line 4-4 thereof;

FIG. 5 is a top plan view of the lockring shown in FIG. 1; and

FIG. 6 is an elevational, partly sectioned view of the lockring shown inFIG. 5.

Referring more particularly to FIGS. 1-4, reference numeral 10designates generally the stud fastener assembly of the invention havinga body 11 provided with external threads 12 and 13. Stud body 11 isshown threaded into workpiece bore 15 of workpiece 16 and in threadedengagement with internal threads 17 or bore 15 of the workpiece. Body 11is further provided with longitudinally extending flutes or serrations14 interposed between the innermost thread convolutions 12a and 13a (asbest seen in FIG. 3) of external threads 12 and 13, respectively.External threads 12 and 13 may be similar or different in size from eachother, but in any event the minimum crest diameters of both of saidthread convolutions must exceed the maximum crest diameter of theinternal serrations of the lockring for reasons which will hereinafterbe more particularly described.

Although not shown, an annular groove may be positioned between theuppermost end of longitudinal serrations l4 and the innermost threadconvolution so as to result in an area of reduced cross section, therebyproviding preselected or preferential breaking or shearing points in theevent of excessive torsional or shearing force applied to the stud body.This avoids a recurring problem whereby under such forces the stud bodynormally fractures approximately one to two thread convolutions belowthe point of contact of the fastener threads with the workpiece borethreads.

Lockring 18 is provided with external serrations 19 and internalserrations 20 (as best shown in FIGS. 5 and 6). Internal serrations 20of lockring 18 are in slidable engagement with longitudinal serrations14 of body 11. AS hereinabove mentioned, regardless of the size ofexternal threads 12 and 13 of body 11, the crest diameters of boththreads exceed the crest diameter of the internal serrations 20 so thatalthough lockring 18 is afforded axial movement relative to the body 11,said movement is limited by the engagement of the upper portion ofinternal serrations 20 with lead thread convolution 12a and theengagement of the lower portion of internal serrations 20 with leadthread convolution 13a. It is thus evident that lockring 18 is made anintegral, captive member of the stud fastener assembly.

As stud body 11 is threaded into bore 15 of workpiece 16, nointerference results from the captive nature of lockring 18 since thelockring will ride axially along serrations 14 of body 11. Further, whenthe upper portion of internal serrations 20 abuts against threadconvolution 12a, further threading of body 11 into the bore of theworkpiece is resisted, thereby indicating that the stud is installed tothe prescribed depth. Therefore, prior to displacing the lockring 18into its locking position it serves the function of providing a positivestop means thereby obtaining uniform installation of the stud fastener.

After the stud fastener is threaded to its predetermined depth, an axialforce is applied to the uppermost portion of the lockring 18, therebyembedding externalserrations 19 thereof into the workpiece materialadjacent counterbore 15a of bore 15. It is obvious that the workpiecematerial located between the crests of the external serrations 19 oflockring 18 provides a resistant force to subsequent rotational movementof the lockring. By virtue of the interengagement of internal serrations20 of lockring 18 and external serrations 14 of stud body 11, rotationalmovement of stud body 11 is also prohibited thereby eliminating thehelical displacement of stud body 11 and maintaining the stud fastenerin tight integral association with the workpiece.

The fastener of the instant invention is made by first externallythreading a stud blank so as to provide the external threads 13. Eitherconcurrent therewith, or immediately subsequent thereto, externallongitudinally extending serrations 14 may be formed. External threads13 may be formed by any conventional means such as thread rolling andthe like, and external serrations 14 may also be formed by anyconventional method such as knurling, grinding, cutting and the like.

After the formation of external threads13 and external serrations 14,lockring 18, upon which is formed external longitudinally extendingserrations 19 and internal serations 20, is slipped over the blank endof the stud body so that internal serrations 20 interengage externalserrations 14 of the body. It should be noted that external threads 13of the body are formed so that the minimum crest diameter thereof islarger than the maximum crest diameter of the external serrations oflockring 18 thereby prohibiting longitudinal disengagement of thelockring.

Thereafter, the unformed end opposite threaded portion 13 of body 11 isthreaded to form external threads 12. External threads 12 are formed bya thread rolling process. Thus, although the unformed portion of body 11over which lockring 18 is slipped must of necessity initially have alesser diameter than the crest diameter of internal serrations 20 oflockring 18, by thread forming, the coats and crests rather than cuttingthe same, the material initially located thereat is caused to flow andbe displaced outwardly so as to form the crest of the threads.Therefore, by use of this process, the crest diameter of the threads soformed will exceed the initial diameter of the blank shank from which itwas formed. Thus, the crest of the external threads 12 are formed tohave a diameter greater than the crest diameter of internal serrations20 of the lockring.

While one embodiment of the invention has been described, it isunderstood that the particular embodiment of the invention hereindisclosed is for illustrative purposes only and that various changes maybe made therein without departing from the principles of the invention.

We claim:

I. A stud fastener assembly for installation in workpiece bores,comprising:

a cylindrical body, said body provided with external threads andexternal longitudinally extending serrations positioned on said bodybetween the said external threads of said body; and

a lockring provided with external longitudinally extending serrationshaving crest and roots and internal longitudinally extending serrationsalso having crests and roots, the latter being interengaged with theexternal serrations provided by said body, the maximum diameter of thecrests of said internal serrations provided by the lockring being lessthan the minimum diameter across the crests of the external threadsprovided by said body.

2. A stud fastener assembly as defined in claim 1, herein the externalthreads are positioned at opposite ends of the body and the externalserrations provided by said body are positioned therebetween.

3. A stud fastener assembly as defined in claim 2, wherein the maximumdiameter across the external longitudinal extending serrationspositioned on the body between the external threads are less than theminumum diameter of the crests of said external threads.

4. A stud fastener assembly as defined in claim 2, wherein the externalserrations of the body extend to the lead convolution of one one of saidthreads provided by said body.

5. A stud fastener assembly as defined in claim 4, wherein aid externalserrations provided by said body extend to the lead convolution of theupper threads of said body.

6. A stud fastener assembly as described in claim 4, wherein theexternal serrations provided by said body extend to the lead convolutionof both threaded portions of said body.

1. A stud fastener assembly for installation in workpiece bores,comprising: a cylindrical body, said body provided with external threadsand external longitudinally extending serrations positioned on said bodybetween the said external threads of said body; and a lockring providedwith external longitudinally extending serrations having crest and rootsand internal longitudinally extending serrations also having crests androots, the latter being interengaged with the external serrationsprovided by said body, the maximum diameter of the crests of saidinternal serrations provided by the lockring being less than the minimumdiameter across the crests of the external threads provided by saidbody.
 2. A stud fastener assembly as defined in claim 1, wherein theexternal threads are positioned at opposite ends of the body and theexternal serrations provided by said body are positioned therebetween.3. A stud fastener assembly as defined in claim 2, wherein the maximumdiameter across the external longitudinal extending serrationspositioned on the body between the external threads are less than theminumum diameter of the crests of said external threads.
 4. A studfastener assembly as defined in claim 2, wherein the external serrationsof the body extEnd to the lead convolution of one of said threadsprovided by said body.
 5. A stud fastener assembly as defined in claim4, wherein said external serrations provided by said body extend to thelead convolution of the upper threads of said body.
 6. A stud fastenerassembly as described in claim 4, wherein the external serrationsprovided by said body extend to the lead convolution of both threadedportions of said body.